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Squealing NPR

Discussion in 'Trucks and Trailers' started by Likestomow, Sep 22, 2006.

  1. Likestomow

    Likestomow LawnSite Senior Member
    Messages: 997

    I have a 1999 Isuzu NPR. With the exhaust brake ON, I hear a loud squeal when I let off the throttle. I have been told that this squeal is due to an exhaust leak. I just had a new muffler installed today and was told the mechanic could not find any exhaust leak anywhere.

    Any ideas?
  2. Picky1

    Picky1 LawnSite Member
    Messages: 38

    If it has an intercooler, it could be leaking from there. Did they do a pressure check on it when they did the exhaust?
  3. Likestomow

    Likestomow LawnSite Senior Member
    Messages: 997

    Isuzu did not do the muffler, a large HD truck center did it. No they did not check the intercooler, but the foreman said the EGR valve had a little soot on it and he said that could be leaking and causing the squeal.

    The noise seems to be right under my seat as I drive.

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